1. Field of the Invention
This invention relates to the detection of atypical epithelia in human patients. More particularly, it relates to an easily used kit which provides a standardized aqueous acetic acid solution and facilitates a standardized method of application of the acetic acid solution to aid in the detection of atypical epithelia by visual examination or colposcopy.
2. Background Information
Detection of atypical epithelial forms in human patients may often be accomplished by simple visual examination or examination with a magnifying instrument. One such diagnostic procedure utilizes a colposcope in the examination of the male and female genital areas for atypical epithelial forms, in particular genital warts or condyloma. The colposcope is a binocular magnifying optical instrument incorporating a light source for stereoscopic visualization of objects under magnification with direct illumination. The colposcope was originally used in cervical examinations.
Early colposcopic procedures introduced the use of dilute acetic acid (approximately 3%) as an aid in cervical examination. It had been found that wiping the cervix with 3% acetic acid prior to colposcopic examination both cleaned the cervix and brought out detail in the cervical architecture. This procedure reduced epithelial transparency and enhanced the grape-like structure of columnar tissue.
More importantly, it was subsequently found that a 3% aqueous solution of acetic acid caused a change in atypical epithelial forms. Whereas dysplastic and neoplastic epithelia naturally showed no distinction in color from normal tissue, such epithelia took on a well-demarcated whitish hue after the application of acetic acid--termed the positive "aceto-white" response. Stronger acetic acid solutions delineated the atypical tissue more quickly but were irritating to mucous membranes. Weaker solutions required a longer waiting period for the appearance of the demarcation.
These observable changes were transient, developing within one minute after application of acetic acid and fading two to three minutes thereafter. Consequently several applications were often necessary before and during the course of an examination.
Colposcopy is used today both alone and in conjunction with cytologic techniques to determine the presence of neoplasia in the visible portion of the female genital tract. Colposcopy is also used in the diagnosis of penile condyloma in men. Application of acetic acid to the penile area prior to visual examination aids in the detection of atypical epithelia in males in the same way as in females--by the formation of aceto-whites. Examination of males is performed either colposcopically or by unaided visual examination.
A few drawbacks in these diagnostic techniques have prevented them from becoming standard techniques. Interpretation of aceto-white patterns requires accurate description of the architecture and utilizes a terminology many physicians find cumbersome. This drawback is exacerbated by the fact that examining physicians do not use a standardized acetic acid solution in the technique. The commonly used solution is household vinegar, which may vary in acetic acid concentration from 3-5+%. Because acetic acid concentration affects the strength and duration of the aceto-white response, this variation in combination with the need to accurately describe the architecture severely limited the utility of the visual diagnosis of condyloma.